Portable audio system having waveguide structure

ABSTRACT

An apparatus includes a housing. A waveguide is located within the housing. The waveguide includes a first subsection that bends around a first axis and has a first cross-sectional area with an aspect ratio that is substantially different from unity. A second subsection bends around a second axis that is non-parallel to the first axis and includes a second cross-sectional area with an aspect ratio that is substantially different from unity. A third subsection acoustically couples the first subsection to the second subsection. The third subsection includes a third cross-sectional area with an aspect ration that varies between the first aspect ratio and the second aspect ratio.

BACKGROUND

Acoustic waveguides have been used in audio systems such as thecommercially available Bose® WAVE® radio, WAVE® Radio/CD, and ACOUSTICWAVE® music systems manufactured by Bose Corporation of Framingham,Mass.

SUMMARY

In one aspect, the invention is embodied in an apparatus that includes ahousing. A waveguide is located within the housing. The waveguideincludes a first subsection that bends around a first axis and has afirst cross-sectional area with an aspect ratio that is substantiallydifferent from unity. A second subsection bends around a second axisthat is non-parallel to the first axis and includes a secondcross-sectional area with an aspect ratio that is substantiallydifferent from unity. A third subsection acoustically couples the firstsubsection to the second subsection. The third subsection includes athird cross-sectional area with an aspect ratio that varies between thefirst aspect ratio and the second aspect ratio.

In one embodiment, the waveguide is fabricated from a plurality ofmoldable parts. At least one of the first, second, and thirdcross-sectional areas includes a rectangular shape. At least one of thefirst, second, and third cross-sectional areas of the waveguide includesa long dimension and a short dimension and the first and secondsubsections each bend around an axis parallel to the long dimension ofthe respective first and second subsection. In one embodiment, the thirdcross-sectional area of the waveguide comprises a long dimension and ashort dimension and a first axis parallel to the long dimension and asecond axis parallel to the short dimension are substantially notrotating when the aspect ratio of the third subsection varies.

The first cross-sectional area and the second cross-sectional area canbe identical. In one embodiment, the first cross-sectional area issmaller than the second cross-sectional area. The aspect of the firstcross-sectional area can be different than the aspect ratio of thesecond cross-sectional area.

In one embodiment, the first axis is substantially perpendicular to thesecond axis. In one embodiment, one of the first and second subsectionsbends around a cavity. The cavity can be sized to reduce a resonancepeak in the waveguide.

The waveguide includes an open end having a shape that facilitates thegrasping of the housing with a plurality of fingers from a single humanhand. A docking cradle can be mechanically coupled to the housing suchthat the docking cradle is capable of being rotated horizontally betweenan open position and a closed position.

In another aspect, the invention is embodied in an apparatus having ahousing. An electronic audio circuit is coupled to the housing. Anacoustic exit that exists the housing. The acoustic exit has a shapethat facilitates the grasping of the housing with a plurality of fingersfrom a single human hand. The acoustic exit is the exit to a waveguideor a port.

The acoustic exit can be located next to an exterior surface of thehousing such that the shape of the open end together with the exteriorsurface facilitates the grasping of the housing with a plurality offingers and the thumb from a single human hand. In one embodiment, theacoustic exit includes a flared end. An inside surface of the acousticexit can include a textured surface. The textured surface can facilitategripping the inside surface of the acoustic exit with the plurality offingers from the human hand.

The housing can substantially encase a portable audio system. A dockingcradle can be mechanically coupled to the housing such that the dockingcradle is capable of being rotated horizontally between an open positionand a closed position.

In another aspect, the invention is embodied in a waveguide. Thewaveguide includes a first subsection that bends around a first axis andhas a first cross-sectional area with an aspect ratio that issubstantially different from unity. A second subsection bends around asecond axis that is non-parallel to the first axis and includes a secondcross-sectional area with an aspect ratio that is substantiallydifferent from unity. A third subsection acoustically couples the firstsubsection to the second subsection. The third subsection includes athird cross-sectional area with an aspect ratio that varies between thefirst aspect ratio and the second aspect ratio.

The waveguide can be fabricated from a plurality of moldable parts. Inone embodiment, at least one of the first, second, and third subsectionsis fabricated from a plurality of moldable parts.

At least one of the first, second, and third cross-sectional areas caninclude a rectangular shape. At least one of the first, second, andthird cross-sectional areas includes a long dimension and a shortdimension and the first and the second subsections each bend around anaxis parallel to the long dimension of the respective first and secondsubsection.

In one embodiment, at least one of the first and second subsectionsbends around a cavity. The third cross-sectional area of the waveguidecomprises a long dimension and a short dimension and a first axisparallel to the long dimension and a second axis parallel to the shortdimension are substantially not rotating when the aspect ratio of thethird subsection varies.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front perspective view of a portable audio system accordingto one embodiment of the invention.

FIG. 1B illustrates another first perspective view of the portable audiosystem of FIG. 1A.

FIG. 1C illustrates a bottom perspective view of the portable audiosystem of FIG. 1A.

FIG. 2A illustrates a front perspective view of a portable energy sourcefor powering a portable audio system.

FIG. 2B illustrates a back perspective view of the portable energysource of FIG. 2A.

FIG. 3 illustrates a partially exploded view of a docking cradle of theportable audio system.

FIG. 4 illustrates a bottom view of a section of the housing thataccommodates the docking cradle.

FIGS. 5A-5C illustrate, respectively, a top view, a front view and aside view of the portable audio system.

FIG. 6A illustrates a rear perspective view of the portable audiosystem.

FIG. 6B illustrates another rear perspective view of the portable audiosystem.

FIG. 7A is a perspective view of a waveguide according to one embodimentof the invention.

FIG. 7B is an exploded view of the waveguide of FIG. 7A.

FIG. 8 is a perspective view of the interior of the portable audiosystem illustrating a waveguide.

DETAILED DESCRIPTION

Exemplary acoustic waveguides can be found in U.S. Pat. Nos. 4,628,528and 6,278,789 and patent application Ser. No. 10/699,304, filed Oct. 31,2003.

FIG. 1A is a front perspective view of a portable audio system 100. Theportable audio system 100 includes a housing 102 and a docking cradle104. A portable music player such as a MP3 player 106 is shown connectedto the docking cradle 104. The docking cradle 104 can be rotatedrelative to the housing 102 as will be discussed in detail herein. Theportable audio system 100 can also include one or more controls 110, 112located on a side surface 114 of the housing 102. For example, thecontrols 110, 112 can be volume controls, track selection controls,skip, stop, pause, rewind, fast forward. and/or play control or can bedesigned to control any other desired function. Additionally, thecontrols can be located on any desired surface of the housing 102. Inone embodiment (not shown), the control functions can be activated via aremote control with or without physical controls on the housing 102. Theremote control can be an infrared (IR) remote or a radio frequency (RF)remote. In one embodiment (not shown), a front surface 116 (FIG. 1B) ofthe housing 102 can include a display. For example, the display can bean LCD display that is capable of displaying information, graphicsand/or video images.

FIG. 1B illustrates another front perspective view of the portable audiosystem 100 of FIG. 1A. In this view, the docking cradle 104 is shown inthe closed position relative to the housing 102. In one embodiment, anexposed surface 115 of the docking cradle 104 is substantially flushwith a front surface 116 of the portable audio system 100.

FIG. 1C illustrates a bottom perspective view of the portable audiosystem 100 of FIG. 1A. The docking cradle 104 is shown in the openposition. The portable audio system 100 can include a portable energysource 120, such as a battery that is secured to the rear surface 121 ofthe housing 102 of the portable audio system 100 with a screw 122. Othertechniques for securing the portable energy source 120 to the housing102, such as a latching mechanism, can also be used. The battery can bea rechargeable battery. The portable energy source 120 is described inmore detail herein.

The portable audio system 100 can also include a power input terminal123 for connecting an external power source (not shown) to the portableaudio system 100. The external power source can supply power to theportable audio system 100 and can also charge the portable energy source120. An auxiliary audio input terminal 124 can be used to connect anexternal audio source (now shown) to the portable audio system 100. Theexternal audio source (not shown) can include a MP3 player, a CD player,a DVD player, a satellite radio, a terrestrial radio, a tape player, aPDA, a computer, a cellular telephone, and/or a digital camera.

The bottom surface 126 of the housing 102 can include feet 128. The feet128 can be fabricated from rubber, plastic, silicone, polypropylene, orany other suitable material. In one embodiment, the feet 128mechanically isolate the portable audio system 100 from the surface onwhich it sits. The feet 128 can also prevent the portable audio system100 from “walking” across the surface when the portable audio system 100is outputting an audio program. A foot 129 can also be attached to abottom surface 130 of the portable energy source 120.

FIG. 2A illustrates a front perspective view of a portable energy source120 for powering a portable audio system 100. In one embodiment, theportable energy source 120 is a rechargeable battery pack. Therechargeable battery pack can include one or more NiCad cells, NiMHcells or Li-ion cells. An aperture 132 for a securing mechanism is alsoshown. The securing mechanism secures the portable energy source 120 tothe housing 102 (FIG. 1C). The securing mechanism can include a screwthat mates with a nut, threaded insert or PEM in the housing 102. Thescrew can be a thumb screw or can include slots that mate with a flathead or Phillips head screwdriver, for example. The portable energysource 120 can be designed to have any desired shape and/or size.

FIG. 2B illustrates a back perspective view of the portable energysource 120 of FIG. 2A. The portable energy source 120 includes aconnector 134. The connector 134 can include multiple conductors 136.For example, the conductors 136 can carry power as well as data signals.The data signals can include information such as charge rate, current,voltage, charge history, capacity, charging parameters, cell chemistry,or any other data related to the portable energy source 120. Theaperture 132 of the securing mechanism for securing the portable energysource 120 to the housing 102 is also shown.

FIG. 3 illustrates a partially exploded view of a docking cradle 150 ofthe portable audio system 100. The docking cradle 150 is designed torotate from a closed position in which a connector 152 is concealed bythe housing 102 to an open position in which the connector 152 isaccessible to an external audio source (not shown). Specific contacts inthe connector 152 can supply power to a docked external audio source.The power can be used to activate the external audio source and/or tocharge a rechargeable battery within the external audio source. Specificcontacts in the connector 152 can carry audio signals from the externalaudio source to circuitry within the portable audio system 100 (FIG.1A).

The docking cradle 150 can be coupled to the housing 102 through variousmechanical techniques. In one embodiment, the docking cradle 150includes an aperture 154 having a lip 156. A hollow rod 158 or tube thatis coupled to the housing 102 fits inside the aperture 154 such that thedocking cradle 150 rotates around the hollow rod 158. The lip 156provides a bearing surface that allows the docking cradle 150 to rotateabout the hollow rod 158. The hollow rod 158 also acts as a conduit forcables 160 emanating from the docking cradle 150 that terminate insidethe housing 102.

In one embodiment, the docking cradle 150 also includes a gear or pinion162 that is coupled to a vicious damper (not shown). The vicious dampercan be embedded within the docking cradle 150. The vicious damper canalso be viscous grease applied to the gear or pinion 162. The viscousdamper allows the docking cradle 150 to rotate smoothly from the closedposition to the open position and vice versa. The pinion 162 engages arack (not shown) that is located within the housing 102.

The docking cradle 150 also includes a stop 164 that is positioned toprevent the docking cradle 150 from over-rotating in the open position.The stop 164 on the docking cradle 150 mates with a feature (not shown)inside the housing 102.

The docking cradle 150 also includes a latching mechanism 166 that locksthe docking cradle 150 in the closed position and prevents the dockingcradle 150 from inadvertently rotating to the open position. Thelatching mechanism 166 engages with a catch (not shown) that is locatedinside the housing 102. In one embodiment, the latching mechanism 166includes a non-spring loaded latch. Other latching techniques can alsobe used. For example, the latching system can include a spring-loadedtouch latch (not shown).

In one embodiment, the docking cradle 150 can rotate by about 170.0degrees. The 170.0 degree angle allows a portion of the docking cradle150 to remain concealed by the housing 102 when the docking cradle 150is in either the open or closed positions. It should be noted that thedocking cradle 150 can be designed to rotate by any desired amount.

In one embodiment, the docking cradle 150 is mounted to the housing 102such that various electrical and mechanical features on the dockingcradle 150 are located on the portion of the docking cradle 150 that isalways concealed by the housing 102. For example, the pinion 162, thelatching mechanism 166, the stop 164, the cables 160, and the hollow rod158 are concealed by the housing 102 when the docking cradle 105 iseither in the open position, the closed position, or any transitionalposition between the open and the closed positions.

The docking cradle 150 also includes a pocket 170 that accepts adapters(not shown) that correspond to various external audio sources. Forexample, each adapter is designed to receive a specific external audiosource having a particular size and shape. In one embodiment, eachadapter includes a slot that allows the connector 152 to mate with aconnector on the external audio source. In another embodiment, eachadapter includes a connector interface that is configured to route powerand data signals between individual external audio sources and theportable audio system 100.

FIG. 4 illustrates a bottom view of a section 180 of the housing 102that accommodates the docking cradle 150. The section 180 includes arack 182 that engages the pinion 162 (FIG. 3) including the viscousdamper on the docking cradle 150. The rack 182 can be secured to thehousing 102 using various techniques. In one embodiment, the rack 182 ismolded into the housing 102. The rack 182 and pinion 162 provide acontrolled motion when the docking cradle 150 is transitioned betweenthe closed position and the open position. In this embodiment, the shapeof the rack 182 is semi-circular having a specific radius. However, therack 182 can be any suitable shape and/or size. Additionally, the numberand size of the teeth on the rack 182 and pinion 162 can be selectedbased on design parameters.

The section 180 of the housing 102 also includes the catch 184 thatengages the latch 166 (FIG. 3). The latch 166 engages the catch 184 whenrotation the docking cradle 150 to the closed position. The latch 166disengages the catch 184 when the right side of the docking cradle 150is pushed towards the housing 102. Other latching mechanisms can also beused such as a spring loaded touch latch.

FIGS. 5A-5C illustrate, respectively, a top view, a front view and aside view of the portable audio system 100 of the present invention. Thetop view of FIG. 5A shows the docking cradle 150 in the open position. Afront surface 190 of the portable audio system 100 includes a curvedshape. The front surface 190 can also have a flat shape or any otherdesired shape. The portable energy source 120 is shown attached to therear surface 192 of the portable audio system 100.

FIG. 5B illustrates a front view of the portable audio system 100. Atextured grille 194 is applied to the front surface 190. Acoustic energyfrom drivers (not shown) inside the portable audio system 200 radiatesthrough the grille 194 substantially unimpeded. Additionally, the grille194 is designed to protect the drivers from external debris whileproviding a finished appearance to the portable audio system 100. Thegrille 194 can be fabricated from metal, plastic, cloth or any othersuitable material.

FIG. 5C illustrates a side view of the portable audio system 100. Thefront surface 190 of the portable audio system 100 is set to apredetermined angle 196 relative to a vertical plane 198. In oneembodiment, the angle 196 is 11.5 degrees. Other angles can also beused. The angle provides an upward tilt to the front surface 190 of theportable audio system 100. Additionally, the angle provides increasedmechanical stability to the portable audio system 100. In someembodiments, an external audio source, such as a MP3 player can includean angled base which causes the external audio source to lean at adifferent angle when inserted into the docking cradle 150. In thisexample, the docking cradle 150 can be independently tilted to maintainthe angle specified by the manufacturer of the external audio source.Alternatively, a docking cradle adapter or insert can be used having ashape that facilitates the proper positioning of the external audiodevice. For example, if the lean angle on an external audio device is15.0 degrees and the lean angle of the portable audio system 100 is 11.5degrees, than the docking cradle 150 can include a lean angle of 3.5 tocompensate for the difference. In one embodiment, a bottom surface ofthe pocket 170 of the docking cradle 150 shown FIG. 3 can be oriented atany desired angle relative to the front surface 190 of the portableaudio system 100.

FIG. 6A illustrates a rear perspective view of a portable audio system100. The portable energy source 120 is shown attached to the rearsurface 192 of the housing 102 though the securing mechanism 122. Theaudio input terminal 124 is configured to accept an external audiosource. For example, the audio input terminal 124 could be an RCA jack,a 3.5 mm jack, a digital input, or any other suitable connector. In oneembodiment, the input power connector 123 receives DC voltage from an ACadapter. In another embodiment, the input power connector 123 can alsobe configured to receive AC power. The controllers 110. 112 are shown onthe side surface 114 of the housing 102.

An open end 200 of a waveguide 202 is also shown exiting the backsurface 192 of the housing 102. The open end 200 can be shaped and sizedto function as handle for the portable audio system 100. A similarlocation and shape can also be used for the exit of a port in a portableaudio system utilizing a ported acoustic enclosure (not shown) insteadof a waveguide. The opening for either waveguide or port can genericallybe referred to a an acoustic exit. For example, the open end 200 can beshaped to facilitate the grasping of the housing 102 with multiplefingers from a human hand. The handle can be used to move the portableaudio system 100.

In one embodiment, the waveguide 202 includes a flare positioned at theacoustic exit 200. The acoustic exit 200 can also include a texturedsurface on an interior surface of the waveguide 202. The texturedsurface provides a griping surface for the fingers. The textured surfacecan be formed into the surface of the waveguide 202. For example,grooves can be engraved into the material in which the waveguide 202 isformed. Alternatively, a textured pad can be adhered to the interiorsurface of the waveguide 202. The textured pad can include an abrasivesandpaper material. Other techniques for creating a textured surface canalso be used.

FIG. 6B illustrates rear perspective view of the portable audio system100 of FIG. 6A. One technique to carry the portable audio system 100 isshown. One or more fingers 204 of a human hand 206 are inserted into theacoustic exit 200 of the waveguide 202. The thumb 208 of the hand 206can rest against the front surface 190 (FIG. 5A) of the portable audiosystem 100. Alternatively, the thumb 208 can rest against a top surface210 of the portable audio system 100.

FIG. 7A is a perspective view of a waveguide 250 according to oneembodiment of the invention. The waveguide 250 includes a firstsubsection 252 and a second subsection 254. The first subsection 252bends around a first axis 256 and the second subsection 254 bends arounda second axis 258. The cross-sectional area of the waveguide 250 can bein the shape of a rectangle including a long dimension 260 and a shortdimension 262. In a waveguide having a cross-sectional area with anaspect ratio that is substantially different from unity, the waveguideturning around an axis parallel to the long dimension has been shown toreduce undesired noise as compared to turning around an axis parallel tothe short dimension. Thus, in one embodiment, the waveguide in the firstsubsection 252 bends around the axis 256 parallel to the long dimension260 and in the second subsection 254 bends around the axis 258 parallelto the long dimension 260. Although the waveguide 250 is shown having asubstantially rectangular cross-section, any other suitable shape canalso be used, such as an oval shape. The aspect ratios of the firstsubsection 252 and the second subsection 252 may or may not be the same.

In one embodiment, the second axis 258 is not parallel to the first axis256. For example, in the embodiment shown, the second axis 258 lies in aplane that is perpendicular to the first axis 256. In one embodiment,each bend is a ninety degree bend. However, the magnitude of the bendcan be any desired amount.

A third subsection 164 acoustically couples the first subsection 252 tothe second subsection 254. The third subsection 264 includes a firstcross-sectional area having a first aspect ratio substantially matchingthat of the first subsection 252. The third subsection 264 includes asecond cross-sectional area having a second aspect ratio substantiallymatching that of the second subsection 254. The aspect ratio of thethird subsection 264 varies smoothly from the first aspect ratio to thesecond aspect ratio.

Although the third subsection 264 connecting the first 252 and secondsubsections 254 can be twisted in order to transition from the firstaspect ratio to the second aspect ratio (from the first axis 156 to thesecond axis 258), the waveguide, which is normally constructed of aninjection moldable material such as plastic, would thus be a difficultstructure to mold that would require complex tooling. FIG. 7B is anexploded view of the waveguide 250 of FIG 7A, illustrating a simple,easily moldable waveguide structure. As shown, the first aspect ratio285 (cross section cut through the A-A′ plane) of the third subsection264 and the second aspect ratio 286 (cross section cut through the B-B′plane) are represented as cross sections having long and shortdimensions in the X-Y axis, with the long dimension in the X-axis at thefirst aspect ratio 285 and the long dimension in the Y-axis at thesecond aspect ratio 286, whereby the X-axis and the Y-axis do not rotatein the transition from the first aspect ratio 285 to the second aspectratio 286 but rather the dimension in the X-axis gradually changes fromthe long dimension to the short dimension and the dimension in theY-axis simultaneously gradually changes from the short dimension to thelong dimension. In contrast, a twisted waveguide will have a rotatingX-Y axis. The embodiment of FIGS. 7A and 7B produces a structure that iseasier to mold than the twisted waveguide. It should be noted that, ifthe cross sectional area of A-A′ is the same as the cross sectional areaof B-B′, the cross sectional area of the third subsection 264 shouldremain constant during its transition. Alternatively, if the overallwaveguide comprises a changing cross sectional area according to apredetermined law related to position along the waveguide, that lawshould be maintained in the third subsection 264 during its transitionfrom the first aspect ratio to the second aspect ratio.

In one embodiment, the waveguide 250 is fabricated from multiple parts.For example, the waveguide 250 can be fabricated from a first part 280and a second part 282. The parts 280, 282 can be molded through knownmanufacturing techniques. For example, the parts 280, 282 can be rigidformed by an injection molding process using a synthetic resin, such asLUSTRAN™ 448 (Bayer Corporation, Elkhart, Ind.). The first part 280corresponds to a main body of the waveguide 250 and the second part 282corresponds to a cover section. Part 280 can be molded using simpletooling and with a single action in the molding machine. The two parts290, 282 can be molded separately and then bonded together. Othertechniques for fabricating the waveguide 250 can also be used.

FIG. 8 is a perspective view of the interior of the portable audiosystem 100 illustrating a waveguide 300. The waveguide 300 can bedescribed as a split waveguide structure which includes a trunkwaveguide section 302 and two branch waveguide sections 304 a, 304 b.Junction ends 306 a, 306 b of the branch waveguide sections 304 a, 304 bare coupled to the trunk waveguide section 302. The long dimension ofthe cross section of the open end at the top 308 of the trunk can beoriented differently than the long dimension of the cross section at thejunction end 310. This change in the orientation of the long dimensionallows the trunk waveguide section 302 to bend around the shortdimension 312 of its cross-sectional shape at the top 308 of the trunkwaveguide section 302. Additionally, the aspect ratio at the junctionend 310 of the trunk waveguide section 302 can be differently from theaspect ratio at the junction end 310 of the trunk waveguide section 302.

Each of the branch waveguide sections 304 a, 304 b is wrapped around anempty cavity 314 a, 314 b. The cavities 314 a, 314 b are partiallyformed by two walls. A vent 316 along with cavities 314 a, 314 b forms aresonant peak reducing mechanism. Since the waveguide is wrapped arounda “double wall”, a large turning radius for the branch waveguidesections 304 a, 304 b is provided. Additionally, the volume and lengthof the cavities 314 a, 314 b can be chosen to reduce any undesiredresonant peak due to the nature of the waveguide 300.

The housing 102 include the waveguide 300 having first left and rightsubsections 320 a, 320 b that contain left and right acoustic drivers322 a, 322 b. The drivers 322 a, 322 b each include a radiating surfacewith a first side facing free air and a second side, opposite the first,facing into the housing 102 and feeding acoustic waves into the branchwaveguide sections 304 a, 304 b.

Each branch waveguide section 304 a, 304 b is a folded continuous tubedefining an interior passage and extending from one of the first leftand right subsectionns 320 a, 320 b containing the drivers 322 a, 322 bat either end of the waveguide to a branch junction 324. The trunkwaveguide section 302 extends from the branch junction 324 to a singletrunk opening 326 having a flared end. Each of the folds definessubsections within each branch waveguide section 304 a, 304 b. Eachsubsection is bounded by baffles or panels extending from the front tothe rear of the waveguide. The housing 102 can also support othercomponents such as an integrated MP3 player, a CD player, a radio, a AMantenna, an amplifier, and/or a power supply, for example.

The first left and right subsections 320 a, 320 b, respectively, arepartially formed by the outside surfaces (facing the drivers) of taperedfirst panels 322 a, 322 b adjacent the drivers 322 a, 322 b and extendto the second subsections 334 a, 334 b. The second subsections 334 a,334 b are formed by the inside surfaces (facing the trunk waveguidesection 302) of the tapered first panels 332 a, 332 b and an outsidesurface of second panels 336 a, 336 b and extend to the thirdsubsections 338 a, 338 b.

Generally, each of the panels is a curved surface extending from thefront or back of the waveguide and includes a free edge. A contouredpost 340 is formed at various free edges to reduce losses and turbulenceof the acoustic pressure waves. The third subsections 338 a, 338 b areformed by the inside surfaces of the second panels 336 a, 336 b and theoutside surface of third panels 342 a, 342 b. Left and right cavities314 a, 314 b are formed by the inside surfaces of the third panels 342a, 342 b and the outside surfaces of fourth panels 344 a, 344 b.

The fourth subsections 346 a, 346 b are formed by the inside by theinside surfaces of the fourth panels 344 a, 344 b and the outsidesurface of the trunk waveguide section walls 348 a, 348 b and extend thethird subsections 338 a, 338 b to connect with the trunk waveguidesection 302 at the branch junction 324.

In one embodiment, the cross-sectional area of each of the branchwaveguide sections 304 a, 304 b continuously decreases along a path fromthe first left and right subsections 320 a, 320 b to the branchjunctions 324. The first and seconds subsections are relatively largeand can be more tapered compared with the third and fourth subsectionsand the common trunk waveguide section.

In one embodiment, the total volume and cross-sectional are profiles ofthe left and right branch waveguide sections 304 a, 304 b are similar.However, the left and right branch waveguide sections 304 a, 304 b canbe asymmetrical because of the need to accommodate the packaging ofdifferently-sized electronic components within the housing 102.

The vent 316 can be located proximate to the branch junction 324. Thevent 316 connects the left and the right cavities 314 a, 314 b to thetrunk waveguide section 302. The left and right cavities 314 a, 314 bform acoustic structures that are sized and configured for reducing themagnitude of a resonance peak. The length of the left and right cavities314 a, 314 b are chosen to exhibit a resonance behavior in the frequencyrange where it is desired to control the magnitude of a resonance peakin the waveguide. The left and right cavities 314 a, 314 b are designedsuch that the acoustic pressure due to the resonance in each cavity,that is present at the branch junction 324, destructively interfereswith the acoustic pressure present within the waveguide 300, thusreducing the peak magnitude.

It should be noted that the location of the vent 316 and the cavities314 a, 314 b are not limited to what has shown in FIG. 8. The locationof the cavities can be anywhere along a general waveguide systemcorresponding to the pressure maximum of the target standing wave andthe particular resonance peak to be attenuated. The use of such cavitiesfor damping out a resonance peak is not limited to waveguide havingcommon trunk and branch section configurations.

By establishing a vent 316 in the trunk waveguide section 302, a targetfrequency component, 380 Hz in one example is significantly reduced.Resistive acoustical dampening materials can be located proximate thevent 316 and/or in one or both of the cavities 314 a, 314 b. Thecavities 314 a, 314 b can also be bifurcated into multiple cavities forreducing multiple resonance peaks.

Additional information concerning folded waveguides and the used ofcavities for damping out a resonance peak can be found in patentapplication Ser. No. 10/805,440, filed Mar. 19, 2004 and patentapplication Ser. No. 10/914,497, filed Aug. 09, 2004, which areincorporated herein by reference.

The foregoing description is intended to be merely illustrative of thepresent invention and should not be construed as limiting the appendedclaims to any particular embodiment or group of embodiments. Thus, whilethe present invention has been described with reference to exemplaryembodiments, it should also be appreciated that numerous modificationsand alternative embodiments may be devised by those having ordinaryskill in the art without departing from the broader and intended spiritand scope of the present invention as set forth in the claims thatfollow. In addition, the section headings included herein are intendedto facilitate a review but are not intended to limit the scope of thepresent invention. Accordingly, the specification and drawings are to beregarded in an illustrative manner and are not intended to limit thescope of the appended claims.

In interpreting the appended claims, it should be understood that:

-   -   a) the word “comprising” does not exclude the presence of other        elements or acts than those listed in a given claim;    -   b) the word “a” or “an” preceding an element does not exclude        the presence of a plurality of such elements;    -   c) any reference signs in the claims do not limit their scope;    -   d) several “means” may be represented by the same item or        hardware or software implemented structure or function;    -   e) any of the disclosed elements may be comprised of hardware        portions (e.g. including discrete and integrated electronic        circuitry), software portions (e.g., computer programming), and        any combination thereof;    -   f) hardware portions may be comprised of one or both of analog        and digital portions;    -   g) any of the disclosed devices or portions thereof may be        combined together or separated into further portions unless        specifically stated otherwise; and    -   h) no specific sequence of acts or steps is intended to be        required unless specifically indicated.

1. An apparatus comprising: a housing; and a waveguide located withinthe housing, the waveguide comprising a first subsection that bendsaround a first axis and included a first cross-sectional area with anaspect ratio that is substantially different from unity, a secondsubsection that bends around a second axis that is non-parallel to thefirst axis and includes a second cross-sectional area with an aspectratio that is substantially different from unity, and a third subsectionthat acoustically couples the first subsection to the second subsection,the third subsection comprising a third cross-sectional area with anaspect ratio that varies between the first aspect ratio and the secondaspect ratio.
 2. The apparatus of claim 1 wherein the waveguidecomprises moldable parts.
 3. The apparatus of claim 1 wherein at leastone of the first, second, and third cross-sectional areas comprises arectangular shape.
 4. That apparatus of claim 1 wherein at least one ofthe first, second, and third cross-sectional areas of the waveguidecomprises a long dimension and a short dimension and the first and thesecond subsections each bend around an axis parallel to the longdimension of the respective first and second subsection.
 5. Theapparatus of claim 1 wherein the third cross-sectional area of thewaveguide comprises a long dimension and a short dimension and a firstaxis parallel to the long dimension and a second axis parallel to theshort dimension are substantially not rotation when the aspect ratio ofthe third subsection varies.
 6. The apparatus of claim 1 wherein thefirst cross-sectional area the second cross-sectional area areidentical.
 7. The apparatus of claim 1 wherein the first cross-sectionalarea is smaller than the second cross-sectional area.
 8. The apparatusof claim 1 wherein the first aspect ratio of the first cross-sectionalarea is different than the aspect ratio of the second cross-sectionalarea.
 9. The apparatus of claim 1 wherein the first axis is in a planesubstantially perpendicular to the second axis.
 10. The apparatus ofclaim 1 wherein at least one of the first and second subsections bendsaround a cavity.
 11. The apparatus of claim 1 wherein the waveguidecomprises an open end having a shape that facilitates the grasping ofthe housing with a plurality of fingers from a single human hand. 12.The apparatus of claim 1 further comprising a docking cradlemechanically coupled to the housing such that the docking cradle iscapable of being rotated horizontally between an open position andclosed position.
 13. An apparatus comprising: a housing; an electronicaudio circuit coupled to the housing; and an acoustic exit that exitsthe housing, the acoustic exit having a shape that facilitates thegrasping of the housing with a plurality of fingers from a single humanhand.
 14. The apparatus of claim 13 wherein the acoustic exit is theexit to a waveguide.
 15. The apparatus of claim 13 wherein the acousticexit is the exit of a port.
 16. The apparatus of claim 13 wherein theacoustic exit is located next to an exterior surface of the housing suchthat the shape of the open end together with the exterior surfacefacilitates grasping of the housing with a plurality of fingers and thethumb from a single human hand.
 17. The apparatus of claim 13 whereinthe acoustic exit comprises a flared end.
 18. The apparatus of claim 13wherein an inside surface of the acoustic exit comprises a texturedsurface.
 19. The apparatus of claim 18 wherein the textured surfacefacilitates gripping the inside surface of the acoustic exit with theplurality of fingers from the human hand.
 20. The apparatus of claim 13wherein the housing substantially encases a portable audio system. 21.The apparatus of claim 13 further comprising a docking cradlemechanically coupled to the housing such that the docking cradle iscapable of being rotated horizontally between an open position and aclosed position.
 22. A waveguide comprising: a first subsection thatbends around a first axis and includes a first cross-sectional area withan aspect ratio that is substantially different from unity, a secondsubsection that bends around a second axis that is non-parallel to thefirst axis and includes a second cross-sectional area with an aspectratio that is substantially different from unity, and a third subsectionthat acoustically couples the first subsection to the second subsection,the third subsection comprising a third cross-sectional area with anaspect ratio that varies between the first aspect ratio and the secondaspect ratio.
 23. The waveguide of claim 22 wherein at least one of thefirst, second, and third subsection comprises at least one moldablepart.
 24. The waveguide of claim 22 wherein at least one of the first,second, and third cross-sectional areas comprises a rectangular shape.25. The waveguide of claim 22 wherein at least one of the first, second,and third cross-sectional areas comprises a long dimension and a shortdimension and the first and the second subsections each bend around anaxis parallel to the long dimension of the respective first and secondsubsection.
 26. The waveguide of claim 22 wherein at least one of thefirst and second subsection bends around a cavity.
 27. The waveguide ofclaim 22 wherein the third cross-sectional area comprises a longdimension and a short dimension and a first axis parallel to the longdimension and a second axis parallel to the short dimension aresubstantially not rotating when the aspect ratio of the third subsectionvaries.